very nice mate,
as for the exhaust, you can pick up a gd non-resonated centre pipe around £40-70 quid on the forums and ninja,afterburner,tsl backbox around 100-130 depending on condition which will make a massive difference to the sound,
only prob with doing the non resonated centre pipe is it can give the drone effect in the cab depending on how loud the system is, i just turn the music up :headbang